1. Field of the Invention
The present invention relates to a process for producing an ophthalmic lens and more particularly to a process for producing an ophthalmic lens which is a laminate of two lens element.
2. Description of Prior Art
Ophthalmic leses have conventionally been produced by, once a lens prescription is determined, subjecting a semi-finished lens kept in stock to rough grinding, smoothing and polishing so as to meet the prescription. The lens is then typically subjected to surface treatments for the purposes of tinging, surface hardening, reflection prevention, etc.
In this process, however, a final ophthalmic lens product is obtained by, after the determination of a prescription, subjecting a semi-finished lens to a plurality of steps mentioned above, thus requiring a long time from customer's order to the delivery of the final product to the customer.
Further in the above process, since the semi-finished lenses are stored without being subjected to surface treatments until they are processed into a final ophthalmic lens product, the semi-finished lenses may be prone, during storage, to deterioration by surface oxidation when they are made of a glass and deterioration by moisture when they are made of a plastic. Such semi-finished lenses, when deteriorated in properties, are unable to satisfactorily form intended films thereon when subjected to surface treatments for the purposes of tinting, surface hardening, reflection prevention, etc.
Furthermore in the above process, a final ophthalmic lens product can be produced only at factories having equipment necessary for ophthalmic lens production.
As a measure for solving the above problems, there have been kept in stock a great variety of final ophthalmic lens products, by lens material (glass, plastic), by lens focus (single vision, bifocal, trifocal, progressive), by lens application (farsighted, nearsighted, astigmatic), and by lens function (tinging, surface protection, reflection prevention, photochromism, anti-fogging), whereby diversified customer needs have been met. This approach makes the stock control of ophthalmic lenses extremely complex.
Hence, an object of the present invention is to provide a process for producing an ophthalmic lens in a short period of time from receipt of a lens order to product delivery, as compared with the conventional process for producing an ophthalmic lens by subjecting a semi-finished lens to a plurality of steps after an order is received.
Another object of the present invention is to provide a process for producing an ophthalmic lens, wherein surface-treatment layers of lens such as a tinted layer, a protective film layer, an anti-reflection film layer and the like can be formed easily and precisely, unlike the conventional process for producing an ophthalmic lens wherein these surface-treatment layers of lens cannot be formed satisfactorily because a semi-finished lens without surface treatment is kept in stock until an order is received. Accordingly, such a lens may experience property deterioration during storage.
Still another object of the present invention is to provide a process for producing an ophthalmic lens wherein a great variety of ophthalmic lenses can be obtained by simply laminating two lens elements selected from two groups of lens elements kept in stock, as compared with the conventional process of keeping in stock a great variety of finished ophthalmic lens products.
Other objects of the present invention will become apparent from the following descriptions and drawings.